Thanks, Graham. Very useful and a superb job of distilling the essence.
Interesting thing for me is that I've always done this instinctively, and the more I take pictures the more I do it (and the longer it is sometimes before I actually use the camera). My challenge, and the challenge I thought everyone had, is using the camera to reflect the vision. Adams, in his little video clip, says "If you have enough craft, if you've done your homework and your practice, you can then make the photograph you desire."
So, I keep working on it. I'm thankful I get to practice every day. Visualizing is great, but without the craft, I could never be satisfied.